twin 250 power head swap breakin results

[DBClubbs]

Finished up doing both power head swaps and had a great weekend on the water. Followed breakin procedure as closely as possible while still being a curteous boater and got the first three hours done. Both motors pulled back on their own during the one minute wot intervals,but i think my primary filters are to restrictive at 2 micron. What is the recomended filter size for primaries? And yes i installed six new low pressure pumps replaced all the other filters and sent all 12 injectors to brucato. So unless i have a regulator problem im pretty sure its my primary filter restriction.
Also im getting a black oil dripping down the skeg of both motors now that theyve run a bit. The gear oil is new so thats not it. Im guessing its a result of running 25:1 oil for breakin... any comments? Anyone else experienced the same thing?

I flow checked the oil pumps and cleaned and tested the o2 sensors with the harness and everything is in spec. I also drained the fuel tank and splashed in 200 gallons of 90 octane ethanol free gas and 4 gallons of oil. I can only get ethanol free gas in mid grade where i live so i figure thats better than 87 octane corn juice.

Dave

[99yam40]

I am sure Rodbolt has said Yamaha says the 2 micron is too restrictive, just run the 10 micron.

You can monitor the fuel pressure/ vacuum to see if there is a restriction and where.
If it is running out of fuel due to restrictions then the cylinders are running lean, and that is not good on the break in

Sounds like unburned oil residue is what you see.
normally seen when cylinders are not firing and burning properly
but maybe just the extra oil

[DBClubbs]

I pushed to wot the first time and saw one dropping off so i immediately pulled out. The rest of the day i just requested 4500 rpm when i was supposed to go to wot. Which is only 5 minutes for that part of the breakin. They held 4500 fine. Ill get some 10 microns and run again next weekend

Dave